Safety mechanism for elevators



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Patented Nov. 18, 1952 UNITED STATES PATENT OFFICE SAFETY MECHANISM FOR ELEVATORS Albert Zindt, Manchester, N. H., assignor to Amoskeag Machine Co., Manchester, N. H., a corporation of New Hampshire Application August 10, 1950, Serial No. 178,693

1 claim. 1

This invention relates to :a safety catch for elevators, lifts, or the like and has for its primary object to arrest movement of the elevator or lift, whenever the lifting force on the elevator is interrupted.

Another object is to hold an elevator car at substantially the levelv to which it has been brought by lifting force exerted thereon, as soon as the lifting effort has been discontinued.

The above 4and other objects may be attained by employing this invention which embodies among its features shoes carried by an elevator in embracing relation Withthe guides of the elevator, guide engaging cylinders carried by the shoes for wedging action between the shoes and Ithe elevator guides, and means carried bythe elevator and connected with the elevator lifting means for moving the cylinders into wedging engagement with their respective shoes and the adjacent elevator guide rails.

Other features include means carried by the elevator car frame and operatively connected with the shoes, -automatically to move the wedging cylinders into wedging engagement with the elevator car guide rails immediately upon discontinuance of the application of lifting force to the elevator.

In the drawings:

Figure 1 is a fragmentary sectional view lthrough an elevator shaft illustrating a car mounted on guide rails therein and equipped with this improved safety device,

Figure 2 is an enlarged fragmentary sectional view taken substantially along the line 2-2 of Figure l and illustrating the position of the various parts when the car is suspended on its hoist cable,

Figure 3 is a View similar to `Figure 2 showing the movement of the cylinder into wedging engagement against an adjacent lguide rail, which movement takes place upon the discontinuance of lifting effort on the car,

Figure 4 is a perspective view of one of the shoes, and

Figure 5 is a perspective view of one of the cylinder moving elements of the device.

Referring to the drawings in detail a conventional elevator shaft I0 has mounted therein for vertical movement a conventional car, or lift, designated generally I2, which is guided in its vertical movements on vertically extending guide rails I4 and I6 which are conventionally mounted in opposed relation in the elevator shaft I0.

The car I2 is conventionally provided with a suspension frame comprising a pair of vertically extending channel members I8 which straddle opposite guide rails I4 and I6 and are held in spaced parallel relation by floor supporting beams 20 and spaced parallel suspension beams 22 and 24 which extend across the top of the car on opposite sides of the guides I4 and I5 and have mounted intermediate their ends a vertically movable suspension link 26, the lower end of which is provided with a head 28 which engages the under sides of the beams 22 and 24 as will be vreadily understood upon reference to Figure 1. The upper end of the link 26 is provided with an eye 38 in which an elevator suspension `and lift cable 32 is secured in a conventional manner.

Mounted for rocking motion about a pivot 34 which extends between the beams 22 and 24 is a rock arm 36 which lies between the link 26 and the channel I8 adjacent the guide I4. Mounted on the channels 22 and 24 and bridging the space therebetween adjacent the ends thereof near the guide I4 is a plate 38 in which is mounted for vertical movement between the channels 22 and 24 a hook 46 which engages the arm 316 as will be understood upon reference to Figure 1. As shown the hook 46 projects upwardly through the plate 38 and is surrounded adjacent its upper end by a compression co-il spring 42, the upper end of which abuts a stop 44 which may take the form of a nut threaded onto the upper end of the hook 48. As illustrated in Figure 1, the rock arm 36 projects beyond the ends of the beams 22 and 24 and into the space between the flanges of the channel which straddle the guide I4. The opposite end of the rock arm is pivotally coupled at 46 to the link 26 so that as lifting effort is applied to the cable 32 the rock arm 36 will move about its pivot 34 against the eiort of the spring 42 to thus cause the end disposed between the flanges of the channel I8 to move downwardly.

A similar rock arm 48 is pivotally mounted at 56 between the beams 22 and 24 and extends from the link 26 and into the space between the legs or anges of the channel I8 adjacent the guide I6, and like the rock arm 36, the rock arm 48 is pvotally connected at 46 to the link 26. Like the arm 36, the arm 48 has connected thereto adjacent its end remote from the link 26 a hook 52 which extends upwardly through a bridging plate 54 similar to the plate 38 and is surrounded adjacent its upper end by a compression coil spring 56 Which rests on the plate 54 and engages at its upper end a stop 58 which may take the form of a nut threaded on the end of the hook 52. It will thus be seen that the ends of the arms 36 and 481adjacent the channels I8 will be yieldingly held upwardly under the inuence of the springs 42 and 56. Obviously as the ends of the arms 36 and 48 adjacent the channels I8 move upwardly, the pivot 46 will cause the link 26 to move downwardly until such time as lifting eifort is applied to the cable 32.

The channels I8 of the car I2 carry conventional upper and lower guide shoes 60 and 62 respectively which ride on the guide rails I4 and I6 in order to hold the elevator or carriage I2 in proper position in the shaft I0.

Mounted in each channel I8 adjacent the lower end thereof is a shoe designated generally 64 which comprises a block 66 having formed intermediate its ends a guide channel 68, one wall of which is cut away to form a chamber I having an inclined wall I2 against which rides a cylinder 'I4 having peripheral grooves 'I6 formed therein. This cylinder is preferably formed of hardened material and is so proportioned that when in the lower end of the chamber 'I0 and the device is in assembled relation on a guide rail, the cylinder 'I4 remains free, but when said cylinder is moved toward Vthe opposite end of the chamber I0 it Wedges between the wall 'I2 and the adjacent guide rail.

Mounted for sliding vmovement on the shoe 64 and overhanging the open side of the chamber 'I8 is a slide plate 'I8 carrying at one end a laterally extending arm 80 which extends into the chamber 'I0 for engagement with the cylinder 'I4 so that when the slide plate 'I8 is moved in one direction, the cylinder 'I4 will be advanced into the chamber 10 and wedged between the wall I2 thereof and the adjacent elevator guide. In order to mount the slide plate 'I8 on the shoe 64 said slide plate is provided with an elongated longitudinal notch 82 which receives the shank Yof a screw 84 :which is threaded into an opening 86 formed in the shoe 64 adjacent the chamber '10. A rod 88 is attached to the slide plate 'I8 and extends upwardly between the Vflanges of the adjacent channel'member I8 and is connected to the projecting end of the rock arm or lever 36 or 48 according tothe side of the elevator carriage on which the rod 88 is disposed.

A suitable stop pin 90 is carried by the block 66 and projects into 'the chamber I0 adjacent the wider end nthereof in order to cooperate with the arm 80 in holding the hardened cylinder 'I4 in place in the chamber 16.

In operation with the device assembled on an elevator car in the manner illustrated," it will be evident that as lifting eiort is applied to the link 26 bythe cable 32, the arms 36 and 48 will be rocked about their respective pivots 34 and 50 against the effort of their respective springs 42 and 56 tovcause the rods 88 to move downwardly and thus move the slide plates 'I8 downwardly so as to disengage the arms 80 from the cylinders I4 and permit them to fall into the larger end of the chamber 10. This will vallow the carriage to be movedV upwardlyfor downwardly under the nfluence of the cable'32 so long asth'e weight ofthe carriage is suspended on the link 26. Should the 4 cable break, or the car or elevator I2 descend too rapidly so as to permit the arms 36 and 48 to move under the influence of the springs 42 and 56 respectively it will be evident that upward pull will be exerted on the rods 88 so as to cause the arms on the slide plates 'I8 to exert lifting effort on the cylinders 'I4 and cause them to wedge between the walls 12 of the shoes 64 and the guides I4 and I6 in the elevator shaft. In this way downward movement of the elevator I2 will be arrested without in any way impairing the normal operation of the elevator in the shaft I0.

While in the foregoing there has been shown and described the preferred form of this invention, it is to be understood that minor changes in the details lof construction, combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as claimed.

I claim:

In -a safety mechanism for elevators, a, shoe carried at each side of the lower portion of the elevator cage, each having avertical slot engaged with the usual guide rail mounted on the adjacent wall of the elevator well, a pivoted member forming one side of the slot and having its inner side inclined with respect to the opposed side of the slot, an invertedI L-shaped element Imounted for vertical movements on the vpivoted member and having the horizontal portion thereof underlying the lower'ends of the member and slot, a cylinder within the slot supported on the said horizontal portion, a rod extending vertically from the top end of the member, a .pair of transversely disposed rocker 'arms pivoted intermediate their ends on top of the 'cage in end-.to-end relation. means for securing the upper vends of the rods to the outer ends of the arms, Ja vertically movable link having 'a head at its lower end and a cable attaching eye at its upper "end, a pivot coupling between the link and vthe adjacent ends of the arms, and a coil spring associated with each of the arms and adapted to befexpanded when the cage is cable suspended at'the link, at which time the rods and the elements are disposed in'lowered positions so that the cylinders are freely 'sup-` ported in the lower ends of the slots on the 'said horizontal portions, said springs acting to rock the arms in a'mannerY to raise the outer ends thereof to draw the rods and the elements upwardly to cause the cylinders to Wedge between the guide rails and the opposed inclined sides'of the members to prevent the'dropping ofthe cage upon breakage'of the suspension'cable.

ALBERT ZINDT.

REFERENCES vCITED The following references are ofrecord inthe 

